This invention relates in general to allyloxymethylatedpolyamide, and, more specifically, to allyloxymethylatedpolyamide compositions, processes for synthesizing allyloxymethylatedpolyamide, and devices containing allyloxymethylatedpolyamide.
Tough cross linked materials are highly desirable for long life articles and coatings. For some applications, the need for an acid to cross link polymers such as polyamides led to defective products having undesirable physical and electrical properties. For example, cross linking of Luckamide polyamides through acid catalyzed condensation of methoxymethyl groups attached to a polyamide backbone unavoidably produced a low molecular weight molecule which may be trapped in the bulk and sometimes give rise to a bubble defect upon thermal expansion. Moreover, improvements were desirable in mechanical strength and abrasion resistance when exposed to alcohol, hydrocarbons and other solvents.
Electrophotographic imaging members, i.e. photoreceptors, typically include a photoconductive layer formed on an electrically conductive substrate. The photoconductive layer is an insulator in the dark so that electric charges are retained on its surface. Upon exposure to light, the charge is dissipated.
Many advanced imaging systems are based on the use of small diameter photoreceptor drums. The use of small diameter drums places a premium on photoreceptor life. A major factor limiting photoreceptor life in copiers and printers, is wear. The use of small diameter drum photoreceptors exacerbates the wear problem because, for example, 3 to 10 revolutions are required to image a single letter size page. Multiple revolutions of a small diameter drum photoreceptor to reproduce a single letter size page can require up to 1 million cycles from the photoreceptor drum to obtain 100,000 prints, a desirable goal for commercial systems.
For low volume copiers and printers, bias charging rolls (BCR) are desirable because little or no ozone is produced during image cycling. However, the micro corona generated by the BCR during charging, damages the photoreceptor, resulting in rapid wear of the imaging surface, e.g., the exposed surface of the charge transport layer. For example wear rates can be as high as about 16.mu. per 100,000 imaging cycles. Similar problems are encountered with bias transfer roll (BTR) systems. One approach to achieving longer photoreceptor drum life is to form a protective overcoat on the imaging surface, e.g. the charge transporting layer of a photoreceptor. This overcoat layer must satisfy many requirements, including transporting holes, resisting image deletion, resisting wear, avoidance of perturbation of underlying layers during coating. Although various hole transporting small molecules can be used in overcoating layers, one of the toughest overcoatings discovered comprises cross linked polyamide (e.g. Luckamide) containing N,N'-diphenyl-N,N'-bis(3-hydroxyphenyl)-[1,1'-biphenyl]-4,4'-diamine (DHTBD). This tough overcoat is described in U.S. Pat. No. 5,368,967, the entire disclosure thereof being incorporated herein by reference.
Since N,N'-diphenyl-N,N'-bis(3-hydroxyphenyl)-[1,1'-biphenyl]-4,4'-diamine (DHTBD) is sensitive to the oxidative species produced by the various charging devices, a chemical stabilizer is desirable for longer imaging member cycling life. An improved overcoating has been achieved with cross linked polyamide (e.g., Luckamide) and N,N'-diphenyl-N,N'-bis(3-hydroxyphenyl)-[1,1'-biphenyl]-4,4'-diamine (DHTBD) and bis-[2-methyl-4-(N-2-hydroxyethyl-N-ethyl-aminophenyl)]-phenylmethane (DHTPM) as an image deletion stabilizer material. Although excellent overcoatings have been achieved with bis-[2-methyl-4-(N-2-hydroxyethyl-N-ethyl-aminophenyl)]-phenylmethane (DHTPM) as the stabilizer, bis-[2-methyl-4-(N-2-hydroxyethyl-N-ethyl-aminophenyl)]-phenylmethane (DHTPM) is difficult to purify and handle. Moreover, it is expensive, a semi-solid at room temperature and oxidized relatively easily as evidenced by color change of the material during storage. However, since bis-[2-methyl-4-(N-2-hydroxyethyl-N-ethyl-aminophenyl)]-phenylmethane (DHTPM) is soluble in alcohols, the solvents required for forming coatings containing polyamide (e.g. Luckamide), it can be solution coated with a polyamide.
Overcoats should be relatively thin due to their relatively poor charge mobilities. Some of the strength of a thin layer depends on how well secured it is to the substrate on which it is coated. This adhesion can be affected by the choice of solvent mixtures used to coat from. Some solvent systems that produce good films and yield formulations with long pot life produce poorly adhered overcoats. Also, during any cross linking process the morphology at the interface with the underlying layer can change in response to the forces produced by the reaction process thereby adversely affecting adhesion.
Thus, the overcoating layer has many requirements, including hole transport, deletion resistance, wear resistance to both abrasion and corona, coatabillity without producing adverse effects in previously formed layers, and adhesion to the transport layer. In addition to the properties of the final film, the coating solution must also possess certain other properties. Among these are the necessary solids concentration and solution viscosity to achieve the required overcoating layer thickness and a pot life long enough to achieve maximum economy for the coating process.